AD/CON/60 Amdt 4 - Fuel Injection Supply Lines

The central physical components regulated by this AD are the “fuel nozzle supply lines” - the flexible or rigid hoses that carry pressurised fuel from the fuel injector manifold (also called the flow divider or distribution valve) to each individual fuel injector nozzle screwed into the cylinder head. These lines operate under high vibration, temperature cycling, and exposure to fuel, making them susceptible to fatigue cracking, corrosion, and mechanical damage. The AD specifically requires inspectors to look for “evidence of cracking, corrosion, pitting, physical damage and stains caused by fuel leakage”. Each of these terms describes a distinct failure mode: cracking from stress fatigue, corrosion from chemical attack or water ingress, pitting from surface erosion or fretting, physical damage from improper handling, chafing, or impact, and fuel stains indicating a leak that may not yet have produced visible drips.

The “fuel line support clamps” are the brackets or clips that hold the fuel nozzle supply lines in place against the engine structure or cowling. Their purpose is to prevent the lines from vibrating excessively, chafing against adjacent components, or being pulled out of position. The AD demands that these clamps be inspected for “fitment and integrity” and that any clamp not conforming to the engine manufacturer’s published data must be fitted or replaced. That published data typically consists of service manuals, service bulletins, or illustrated parts catalogues issued by Teledyne Continental Motors. The requirement implies that the correct clamp part number, installation location, torque, and orientation must be verified against the most current manufacturer documentation.

“Time in service” is defined in the AD as the 110-hour inspection interval measured in hours of engine operation, not calendar time. This is a standard aviation maintenance metric though it may interact with other scheduled maintenance thresholds such as annual inspections or 100-hour checks. The phrase “next scheduled maintenance” is not further defined in this instrument, but in practice it refers to the next maintenance event that the aircraft would undergo under its approved maintenance program, whether a 50-hour oil change, a 100-hour inspection, or an annual.

The AD also introduces a cross reference to the FAA’s AD 2011-26-04 as originally applicable to Lycoming engines. By extending that FAA AD to TCM engines, CASA aligns Australian requirements with the US regime, but the Australian AD is a standalone instrument with its own compliance schedule. The removal of the CAO 106 reference simply cleans up a regulatory citation that was no longer relevant, as Civil Aviation Order 106 has been superseded by the Civil Aviation Safety Regulations.

The AD bears directly on every person or entity that owns, operates or maintains an Australian-registered aircraft powered by a Teledyne Continental Motors fuel injected horizontally opposed piston engine. This covers a large fleet of light general aviation aircraft, including but not limited to Cessna 172, 182, 206 models equipped with Continental O-470 or IO-470 series engines, Piper PA-28 and PA-32 models with Continental O-360 or IO-360 engines, and numerous homebuilt and experimental category aircraft using TCM powerplants. The wording “all TCM fuel injected horizontally opposed piston engines” is broad: it includes both normally aspirated and turbocharged variants, and both carburetted engines with a fuel injection retrofit and factory fuel injected models. However, engines that are not fuel injected (i.e., carburetted) or that are not horizontally opposed (e.g., radial or vee engines) are outside scope.

Maintenance organisations - both certified repair stations and licensed aircraft maintenance engineers (LAMEs) - are the direct actors who must carry out the inspections and replacements. They bear the compliance burden of correctly interpreting the AD, sourcing the appropriate replacement parts and clamps, and making accurate logbook entries. For operators who perform their own maintenance under a maintenance approval (such as some private owners), the AD imposes the same obligations.

Parts suppliers and distributors are indirectly affected: the requirement to replace defective lines or clamps may increase demand for genuine Continental or approved PMA (Parts Manufacturer Approval) fuel lines and support clamps. Engine overhaul shops may need to incorporate the AD into their standard work scope. Insurers may require evidence of compliance before renewing policies. Aviation fuel suppliers and airports are not directly regulated by the AD but may see a knock-on effect if aircraft are grounded for non compliance.

The supersession of AD/CON/26 means that anyone who had been complying with that older directive by, for example, performing a different inspection schedule or using a different acceptance criterion, must now align with the current one. The extension of the FAA AD to TCM engines also affects aircraft that operate in both the US and Australian regulatory environments; compliance with the CASA AD will generally satisfy the FAA AD for Australian registered aircraft operating under a bi lateral agreement, but operators crossing borders should verify.

The AD imposes four core duties on the person responsible for the continuing airworthiness of the aircraft (typically the registered operator or the maintenance provider). Duty one: inspect every fuel nozzle supply line between the fuel injector manifold and the nozzles at the first eligible maintenance opportunity and every 110 hours thereafter. Duty two: replace any line that shows any of the five specified defects (cracking, corrosion, pitting, physical damage, fuel leakage stains) before the aircraft flies again. Duty three: inspect the support clamps for correct fitment and integrity against the engine manufacturer’s published data. Duty four: fit or replace any clamp that does not meet that published data, again before further flight.

The compliance schedule creates a hierarchy. The inspection duties under requirements 1 and 3 have a grace period until the next scheduled maintenance, but after that they are recurring at 110 hour intervals. The replacement duties under requirements 2 and 4 are immediate: they must be done “before further flight” after the inspection reveals a defect or non conforming clamp. This means that if the inspection is done at a scheduled maintenance event and a defective line is found, the aircraft cannot be released to service until that line is replaced, even if the maintenance event itself is not complete.

Aircraft owners and operators have the right to expect that, if they fully comply with this AD and any other applicable requirements, the aircraft will be considered airworthy in respect of the fuel injection supply system. They also have the right to appeal or seek an alternative means of compliance under the relevant provisions of the Civil Aviation Safety Regulations, although the AD text does not mention any such process. Maintenance providers have the right to charge reasonable costs for the inspection and replacement work, and to refuse to release an aircraft if the required actions are not completed.

There is no specific right created by the AD to operate the aircraft without the fuel nozzle supply lines if defective; that would be a breach. The instrument does not confer any immunity from other regulatory requirements, nor does it grant any intellectual property rights or trade privileges.

This Airworthiness Directive does not itself prescribe specific penalties for non compliance. However, it derives its legal force from the Civil Aviation Act 1988 and the Civil Aviation Safety Regulations (CASR). Under the Australian regulatory framework, operating an aircraft that does not comply with an applicable AD renders that aircraft unairworthy. Doing so constitutes an offence under the Act and Regulations, potentially attracting civil penalties, infringement notices, or criminal prosecution depending on the circumstances.

The instrument is signed by Mike Higgins as a delegate of the CASA, confirming its status as a legislative instrument. Enforcement action is at CASA’s discretion and can include: a direction to ground the aircraft (a “stop” order), suspension or cancellation of the aircraft’s certificate of airworthiness or registration, the issuance of an infringement notice with a monetary penalty, or referral for prosecution through the Commonwealth Director of Public Prosecutions. In practice, CASA often first seeks voluntary compliance, but repeated or deliberate non compliance can lead to significant fines, and in the case of an accident caused by a known defect, the operator or maintainer could face criminal charges for reckless conduct.

The AD itself references fatal accidents attributable to fuel injector supply line failure, underscoring the seriousness with which regulators view the hazard. Maintenance providers and operators who falsify maintenance records or logbook entries to conceal non compliance risk separate offences under the Act, including false document offences which carry heavier penalties.

The cost of non compliance extends beyond regulatory penalty. A fuel supply line failure in flight can cause engine failure or an engine fire, leading to hull loss, personal injury or death. Civil liability claims for negligence or breach of statutory duty may follow. Insurance policies may exclude cover if the aircraft was operated in knowing violation of an AD. The AD imposes no bond or deposit, but the economic risk of non compliance is substantial.

This AD supersedes the earlier airworthiness directive AD/CON/26. Any aircraft that was being maintained under that older directive must now comply with AD/CON/60 Amdt 4 instead. The older directive’s requirements are no longer valid for the engines covered, and operators should not continue to rely on them.

The AD extends the applicability of the United States FAA Airworthiness Directive 2011-26-04 (Amendment 39-16894, or any later FAA approved revision) to Teledyne Continental Motors engines. For Lycoming engines, the FAA AD remains directly applicable in Australia by virtue of the bi lateral airworthiness agreement, but for TCM engines the CASA AD creates a domestic requirement that mirrors the FAA AD. This means that an aircraft with a TCM engine that is compliant with this CASA AD will ordinarily be compliant with the FAA AD for the same system, but operators should confirm with the relevant foreign authority if flying a US registered aircraft in Australia or vice versa.

The AD also removes a reference to CAO 106 (Civil Aviation Order 106) as inapplicable. This cleans up a regulatory cross reference that was obsolete because CAO 106 has been repealed and replaced by the continuing airworthiness provisions in CASR Part 42 (for large aircraft and aircraft used in air transport) or Part 43 (for general aviation). The AD does not alter the underlying hierarchy: ADs sit above manufacturers’ service information, and they are mandatory. Compliance with a manufacturer’s service bulletin or service instruction is not a substitute unless it is equivalent to the AD.

The AD operates within the broader regulatory scheme of continuing airworthiness. An aircraft’s approved maintenance program (AMP) must include any applicable ADs. When a component is replaced under this AD, the replacement must be an approved part - either genuine Continental, or a PMA part approved under the Civil Aviation Safety Regulations. The logbook entry for the AD compliance must be made in accordance with CASR Part 42 or Part 43, as applicable. The AD does not relieve the operator from other requirements such as the periodic replacement of fuel hoses as specified by the engine manufacturer or aircraft type certificate holder.

The instrument recites its own amendment history in the background section. The original AD/CON/60 became effective on 17 September 1992. At that time it applied to TCM fuel injected engines but likely had a different scope and inspection criteria.

Amendment 1 became effective on 31 August 2006. It added the requirement for a visual inspection specifically for the presence of pitting and corrosion in the fuel nozzle supply lines. This amendment was driven by an Australian Transport Safety Bureau (ATSB) investigation report (reference BO/200601291) which determined that pitting and corrosion had been the causal factor behind failure of one of the fuel lines. Before this amendment, the AD may have required only inspection for cracking and physical damage.

Amendment 2 corrected a typographical error in Amendment 1, with no change to the substantive requirements or compliance schedules.

Amendment 3 changed the AD to refer to FAA AD 2011-26-04 Amendment 39-16894 (or the latest FAA approved revision). This introduced the cross reference to the FAA AD and aligned the Australian requirements with the US regime. It appears that before Amendment 3, the AD did not incorporate the FAA AD, and the inspection criteria may have been less aligned.

Amendment 4, the current version, corrects a typographical error noted in Amendment 3 and removes the reference to CAO 106 as it is no longer applicable. Again, no change to the requirements or compliance schedules. The effective date for Amendment 4 is 30 January 2012.

Thus the substantive evolution of the AD has been from a general inspection regime to one that explicitly targets pitting and corrosion (Amdt 1) and then to an internationally harmonised regime referencing the FAA AD (Amdt 3). The later amendments are purely administrative.

The source text of this AD does not refer to any litigation directly. It does cite an ATSB investigation report (BO/200601291) arising from a fuel line failure, but an ATSB report is an accident investigation, not a court case. No mention is made of any judicial review of the AD or any legal challenge to its validity.

That said, the underlying hazard - fuel injector supply line failure - has been a factor in aviation accidents and fatalities. The AD itself states that the FAA has reports of fatal accidents attributable to fuel injector supply line failure because of inadequate maintenance. Those accidents may have given rise to civil tort claims in the United States or elsewhere, but the Australian AD does not detail them.

In Australia, there is no recorded case law interpreting this specific AD in publicly available decisions of the Administrative Appeals Tribunal or the Federal Court. CASA’s decisions to issue or amend ADs are generally not subject to merits review, though they could be challenged on procedural grounds in the Federal Court. The absence of litigation history in the AD document means none is known to the drafter, but it does not foreclose the possibility of proceedings.

Operators and maintainers should be aware that non compliance with the AD, if it results in an accident, would likely be central evidence in any civil negligence case. The AD sets a clear standard of care, and deviation from it would weigh heavily against a defendant.

Several practical traps await those who do not read the AD with care. The inspection interval of “110 hours time in service” is not the same as a calendar interval. An aircraft that flies infrequently may not reach 110 hours for years, meaning the inspection may be triggered only at the next scheduled maintenance. But “next scheduled maintenance” can be ambiguous. If the aircraft has no fixed maintenance schedule (e.g., a private owner operating under a generic 100-hour/annual program), the “next scheduled maintenance” might be the next 100-hour inspection or the next annual. The AD does not define what constitutes scheduled maintenance, so a conservative approach is to treat the first flight after the effective date as the trigger point.

The “before further flight” requirement for replacements can catch operators off guard. If a defect is found during a routine inspection and the replacement part is not immediately available, the aircraft is grounded until the part arrives. This can cause costly delays, especially for remote operators or those with unusual engine variants. There is no grace period for sourcing parts.

The requirement to inspect support clamps “in accordance with the engine manufacturer’s published data” places a burden on the maintainer to locate and interpret the correct Continental Motors documentation. That data may not be readily available for older engine models, and the manufacturer may have superseded the relevant publication. Using an outdated or incorrect clamp specification could lead to a false pass on the inspection.

The AD does not specify the standard for “evidence of” cracking, corrosion, pitting or physical damage. Is a slight surface discolouration a stain indicating a fuel leak? The AD does not define thresholds, leaving room for subjective judgment. This creates a risk of inconsistent application between different engineers or organisations. A cautious engineer may replace a line that another would deem serviceable, driving up costs.

The AD extends to all TCM fuel injected horizontally opposed piston engines, but it does not exclude engines that have been modified with aftermarket fuel injection systems or that have been converted from carburetion. The applicability language should be read strictly, but an operator with a modified engine should verify whether the AD still applies to the fuel injection lines fitted.

Finally, the AD supersedes AD/CON/26, but some operators may have been complying with that older AD by performing a different inspection schedule or using different acceptance criteria. They must now adjust to the current requirements. There is no grandfathering provision for lines previously inspected under the old AD; the new inspection schedule starts afresh.

Compliance with AD/CON/60 Amdt 4 follows a step by step process that should be documented in the aircraft’s maintenance records. The first step is identification: confirm that the aircraft is equipped with a Teledyne Continental Motors fuel injected horizontally opposed piston engine. This includes most light singles and twins with Continental engines that have fuel injection. Carburetted Continental engines are not affected.

Second, determine the compliance date. The AD became effective on 30 January 2012. The first action must be taken at the next scheduled maintenance after that date. If the aircraft was already in a maintenance event on or after that date, the inspection should have been done then. Thereafter, the inspection cycle repeats every 110 hours of time in service.

Third, conduct the visual inspection of every fuel nozzle supply line. Remove any cowling or ducting necessary to access the lines from the fuel injector manifold to the individual fuel injector nozzles. Use a good light source and, if necessary, a borescope for areas not directly visible. Scrutinise the entire length of each line, including the end fittings, for any cracks (particularly hairline cracks near ferrules or bends), corrosion (pitting or rust), physical damage (dents, chafing, kinks), or stains that indicate fuel leakage. Pay special attention to areas where the line contacts clamps or adjacent components.

Fourth, if any of these defects are found, replace the line before further flight. Use only an approved replacement part: a genuine Teledyne Continental Motors line or a PMA approved equivalent. Ensure the new line is properly installed with the correct orientation and clearance.

Fifth, inspect the support clamps. Verify that each clamp is present, correctly positioned, not worn or cracked, and that it secures the line without over tightening or allowing movement. Compare the clamp part number, location and installation method against the engine manufacturer’s published data. This data is found in the engine overhaul manual, maintenance manual, or service bulletins.

Sixth, if any clamp does not meet the published data, fit or replace it before further flight. Use the correct clamp for the specific line position.

Seventh, after completing all actions, make a logbook entry recording the AD reference, the date, the aircraft time in service, that the inspections were performed, any lines or clamps replaced, and the engineer’s details and approval. Keep copies of any manufacturer data used for reference.

Eighth, schedule the next 110 hour inspection. It may be convenient to align this inspection with the aircraft’s 100 hour or annual inspection cycle, but the 110 hour interval must not be exceeded.

For ongoing compliance, maintain a record of the 110 hour interval and ensure that inspections are not deferred beyond that limit. If the aircraft operates infrequently, the calendar trigger of the annual inspection may still govern, but the hour limit is absolute once the hours accumulate.